1. Field of the Invention
The present invention relates to a technology for special effect playback processing and special effect recording processing, such as digest playback and recording, on a recording/playback apparatus that records and plays back information signals, such as video signals and audio signals used in a broadcast program and the like, to and from a predetermined recording medium such as a magneto optical disc, hard disk drive (HDD), and a semiconductor memory. The present invention relates also to a signal processing technology for extracting predetermined featured data from image data and classifying predetermined images using the feature extraction data and predetermined parameter data that are set when the information is transmitted on a predetermined network such as the Internet.
2. Description of the Related Art
When recorded contents recorded for a long time are played back with a conventional VTR or a disc recording/playback apparatus within a shorter time for quickly understanding their content, the playback processing is performed about 1.5 to 2 times faster than the normal playback processing speed considering the speed at which audio information can comprehended.
If an attempt is made to play back the content in a farther shorter time to play back its summary (digest playback), the audio output is too fast to comprehend its content. Therefore, the playback processing is usually performed by outputting only the image without audio sound.
One of the methods for solving this problem is to perform the digest playback in which the predetermined featured data is extracted from the recorded video/audio data, and only the predetermined featured periods are selected and played back according to a predetermined rule, or in which only the predetermined featured periods are selected and played back according to a predetermined rule using predetermined parameter data.
A technology for playing back a video using the featured data is to analyze the video structure by detecting featured data from vide/audio data and then play back the summary by carrying out similar chain detection as disclosed, for example, in Japanese Laid-Open Patent JP2000-285243A.
Furthermore, a technology for detecting a music period from audio signals, which is a technology for browsing a video by detecting audio feature, is described, for example, in Kenichi Minami, et al., “Video Indexing Using Music Information and Its Application” (Collective Papers from The Institute of Electronics, Information and Communication Engineers) (D-2 Vol. J81-D-2 No. 3 pp. 529-537, March, 1998) and Kenichi Minami et al., “Video Browsing Interface Using Audio Information” (Technical Reports from The Institute of Image Information and Television Engineers (Vol. 19, No. 7, pp. 1-6, 1995)).
A technology for skimming through a video from a predetermined image segment or a predetermined audio segment is also known. For example, the technology is found in Japanese Patent Application No. Hei 8-513478 “Method And Apparatus for Creating Searchable Digital Video Library And System And Method for Using The Library” and Japanese Patent Application No. Hei 8-513479 “Method And System for Skimming through Digital Audio And Video Data”.
In addition, it is also possible to classify TV programs or image scenes recorded by a video camera according to similar images for use in editing or in playing back the digest of only the classified image scenes.
For the classifying processing, Japanese Laid-Open Patent JP2002-344872A and Japanese Laid-Open Patent JP2002-344852A disclose a technology for carrying out a predetermined similar image classification according to predetermined featured data and a predetermined threshold and a technology for displaying image data classified according to similarities in a predetermined format.
Depending upon the result of image classification, the desired classifying method may differ according to the user. For example, one user wants to change the classifying method, another user wants to extend the allowable range of similarities for similarity-based classification, and still another user wants to narrow the allowable range. See, for example, Patent Document 1: Japanese Laid-Open Patent JP2002-281449A.